THE PITUITARY BODY 



normal animals or of animals subjected to all the operative 

 procedures except hypophysectomy.'" 



The effects of insulin in hypophysectomized animals. — It has 

 long been known that, as a result of the extirpation of the 

 pituitary body, sensitivity toward insulin is greatly in- 

 creased. The change is due to the removal of the pars glandu- 

 laris and not to removal of the pars neuralis (see the recent 

 articles of Pencharz, Cori, and Russell, 1936; and of Karlik, 

 1936). However, Chaikoff, Reichert, Larson, and Mathes 

 (1935) showed that retraction of the right temporal lobe of 

 the dog (after craniotomy and incision of the dura mater) 

 alone was sufficient frequently to increase insulin-sensitivity 

 even 3 months after operation. There occurred in some ani- 

 mals as much fall in the concentration of sugar and inorganic 

 P in the blood as in hypophysectomized animals. In the in- 

 sulin-sensitive animals, in which operation had been carried 

 only to the stage of temporal-lobe retraction, the pituitary 

 appeared normal; however, the authors suggest that an un- 

 recognized injury of the region about the pituitary had oc- 

 curred. The quantitative studies of Heinbecker, Somogyi, 

 and Weichselbaum (1937) indicated that in the dog insulin- 

 sensitivity is approximately doubled 4 weeks after hypophy- 

 sectomy and, after a year, is quadrupled. 



From the discussion of the metabolism of carbohydrates 

 in hypophysectomized animals it is clear that such animals 

 tend rapidly to use up all available carbohydrate reserves 

 when fasting is imposed, whereas in normal animals some 

 carbohydrate is spared and more fat and protein are oxidized. 

 These facts alone would justify the expectation that the 

 blood sugar would fall to lower levels and that shock would 

 be more easily induced in hypophysectomized animals re- 

 ceiving insulin. Kater (1936) reported new experiments on 

 the insulin-sensitivity of hypophysectomized rats. Whereas 



'' According to Di Benedetto and Di Benedetto (1935), hyperglycemia caused by 

 ether is less in hypophysectomized dogs than in control aimals. However, this 

 would be expected if carbohydrate reserves were low as a result of hypophysectomy. 

 Hyperglycemia caused by morphine (30 mg. per kg.) appeared not to be affected. 



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